The Influence of Dietary Calcium and Phosphorus on the Incidence of Milk Fever in Dairy Cattle

Abstract

Sixty-nine aged Jersey cows were divided into 4 groups and fed diets containing various Ca-P ratios for varying periods of time before parturition. Results indicate that a low-Ca, high-P diet fed during the last mo. of the dry period effectively prevents milk fever. There appeared to be a direct correlation between the Ca-P ratio of the prepartum diet and incidence of milk fever. The postpartal serum Ca levels of cows receiving the low-Ca, high-P diet tended to be higher than those receiving the high-Ca diets, although the results are not statistically significant. The suggestion is made that the low-Ca, high-P diet exerts its milk fever preventive action by inducing a compensatory hypertrophy of the parathyroid gland, thus tending to avert the drop of serum Ca accompanying parturition and early lactation .